Preservative, Optiphen is a specialized blend of Phenoxyethanol in an emollient base of Caprylyl Glycol. This combination provides optimized protection against microbial growth with the added benefit of imparting exceptional feel to our product. Optiphen is paraben free and has no formaldehyde either, making it a great preservative of choice for many products needing effective protection against mold, and bacteria.